1. Field of the Invention
This invention most generally relates to a method and device for flame switching the flame from a single burner tube in order to associate the flame and the energy of the flame with different and distant energy using systems.
This invention more generally relates to gas stoves used either commercially and/or in the home having a bake oven which may be self-cleaning and may have broil capability. More particularly the invention relates to a new flame switchable gas burning device or assembly which may be placed at the top rear corner of the oven cavity. The functions of bake, broil and self-clean are accomplished with a single burner tube in which the flame is switched in order to operate in the broil or in the bake/self-clean mode. In the broil mode the radiant heat to the broiled products is indirect radiant heat in that the flame does not "see" the broiling products.
2. Description of the Prior Art
Common gas oven configurations can be divided into two approaches: "The single cavity for bake and broil, and an oven which features a large bake cavity and a smaller drawer for broiling. The single cavity designs use two separate burners to achieve bake and broil conditions whereas the two compartment approach shares a common burner.
To achieve bake conditions the single oven utilizes a gas burner subassembly located under the floor of the oven. The hot products of combustion flow through openings in the oven floor and heat the oven surfaces and interior space. This method of heating prevents the baked goods from looking directly at the burner. Broiling is accomplished by exposing the top surface of the food product directly to a highly radiant burner subassembly.
In a single oven approach, a separate broil burner is mounted at the top of the oven cavity looking directly down on the oven space. Typical broil burners are radiant screen or blue flame burner where the flame rolls over a metal spreader. With either approach, the burner looks directly at the food imparting a high radiant heat flux to the product. A single oven cavity approach is the typical configuration used for obtaining pyrolytic cleaning or self-cleaning oven performance. This cleaning process occurs when the soiled surfaces of the oven cavity reach temperatures in excess of 800.degree. F. which usually corresponds to oven air temperatures in the range of 875.degree. F. to 925.degree. F. Maintaining this high temperature condition for an extended period of time will result in the reduction of food soils to a powdery ash residue. This cleaning process is most effective except in the regions of the door gasket where the short conduction paths to the cooler door result in somewhat cooler surfaces with resulting reduction in cleaning performance.
This single cavity gas range is a relatively recent advancement in oven design. In the older design, the oven is configured with a large baking oven cavity and a lower smaller broiler cavity. A single burner is mounted between the two cavities and this burner looks directly into the broiler drawer for the desired radiant input to the food. During bake the hot gases produced by the single burner flow through the oven floor into the bake cavity. This oven design is not typically or readily adapted or adaptable for self-cleaning temperatures.
U.S. Pat. No. 3,973,551 to Caselini et at discloses an arrangement which is substantially different from the subject invention in that it uses a single bottom burner combined with a recirculating fan or blower for circulating hot air throughout the oven. While the specification indicated that the oven can direct substantial heat from the top area, it is not specifically seen to disclose a capacity for broiling in the conventional sense.
German AS No. 1 241 080 is of interest as regards the disclosed invention in that it illustrates the use of a single top burner and a recirculating fan for heating an enclosed oven cavity. However, hot gases are not circulated through the oven, but rather around the oven cavity. Thus, there is not observed a broiling capacity and the overall arrangement is substantially different from the subject invention.
U.S. Pat. No. 3,659,579 to Henderson et al shows an oven capable of baking and broiling, as well as self-cleaning. A single burner at the top of the oven is utilized as both a broiling and baking burner, with a recirculating fan arranged to move hot air and products of combustion throughout the oven space. It is to be noted that broth broiling and baking heat are supplied from the top of the oven, with the burner having a two-position configuration for broiling or baking. The overall arrangement of the burner and recirculating fan are seen to be considerably different from that used the the subject invention as disclosed herein by Applicant.
U.S. Pat. No. 3,437,085 to Perry shows a single top burner arrangement for an oven that can bake, broil or self-clean. However, there is not seen to be disclosed in this patent any arrangement comparable to the recirculating/diverting fan arrangement used in the subject invention.
In addition to the comments above, it should be further noted that while both Henderson and Perry offer broiling and baking, they differ significantly from Applicant's Invention in that both use forced air (pressurized) burners and Henderson must use a manually operated damper to move between broil and bake as compared to flame switching and Perry uses two gas lines, three burner to move between broil and bake modes.
It would be advantageous to provide a gas fired oven having one burner which would operate in the broil, bake and self-clean mode and which would use one burner device and one oven cavity which would be used for both broiling and baking. It would also be advantageous if the oven did not require the use of complicated controls and devices in order to effect acceptable broiling and baking and where the emission standards and performance standards are met and/or exceeded using simple devices and simple controls.